Bulk Material Handling System

ABSTRACT

A bulk material handling accessory such as a conveyor belt cleaner for use in connection with a bulk material handling system. The bulk material handling accessory includes a main frame, a scraping member including an arm and a scraper blade pivotally attached to the main frame, and a damper mechanism coupled at one end to the main frame and at another end to the scraping member. A mounting mechanism is attached to the main frame for providing linear and rotational movement of the main frame and the associated scraping member and damper mechanism. The damper mechanism includes a damper having a piston and a housing having a fluid chamber. The viscosity of the fluid within the fluid chamber is selectively changeable to change the damping characteristics of the damper mechanism to accommodate changes in operating conditions.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/824,103, filed Aug. 31, 2006, and U.S. Provisional Application No.60/885,084, filed Jan. 16, 2007.

BACKGROUND

Bulk material handling apparatus are used in connection with the storageand movement of bulk materials such as grain, sand, gravel, coal and thelike. Bulk material handling apparatus include primary apparatus andsecondary or accessory apparatus. Primary apparatus include conveyors,conveyor transfer points, transfer chutes, bins, silos, hoppers,associated structures and the like. Accessory apparatus include conveyorbelt cleaners, air cannons, industrial vibrators, belt tracking devicesand the like that are used in combination with primary bulk materialhandling apparatus. For example, accessory apparatus such as air cannonsand industrial vibrators are used in combination with primary apparatussuch as transfer points, transfer chutes, bins, silos and hoppers tofacilitate and control the flow of bulk material through the primaryapparatus and improve the performance of the primary apparatus.Similarly, secondary apparatus such as conveyor belt cleaners are usedin combination with primary apparatus such as conveyors to improve theperformance of the primary apparatus.

In some cases, such as in the combination of an industrial vibrator witha transfer chute, the accessory apparatus is adapted to createvibrations and to transfer vibrations to the primary apparatus to inducethe flow of bulk material through the primary apparatus. In other cases,such as in the combination of a conveyor belt cleaner with a beltconveyor, vibration of the belt cleaner accessory apparatus with respectto the belt conveyor primary apparatus is preferably reduced oreliminated.

Conveyors include an endless belt for moving bulk materials from onelocation to a second location. As the bulk material is discharged fromthe conveyor belt, a portion of the bulk material often remains adheredto the belt. Conveyor belt cleaners having one or more scraper bladesare used to scrape the adherent material from the belt and thereby cleanthe belt. The scraper blades of a conveyor belt cleaner are typicallyattached to a cross shaft that extends transversely across the width ofthe conveyor belt. The conveyor belt cleaner may include one or moretensioning devices that bias the scraper blades into engagement with theconveyor belt with a force that provides a scraping pressure between thescraper blade and the belt. The scraping edge of each scraper bladewears during use due to its scraping engagement with the moving conveyorbelt. Tensioners move the scraper blades as the scraper blades wear tomaintain the scraper blades in biased scraping engagement with theconveyor belt.

In order to obtain adequate performance from the conveyor belt cleaner,the scraper blades are biased into scraping engagement with the conveyorbelt with a selected amount of force to generate a desired scraping orcleaning pressure between the scraper blade and the belt, and that thescraper blades be disposed at a selected cleaning angle with respect tothe belt depending upon operating conditions. If the scraper blades arebiased against the conveyor belt with an excessive amount of force, thismay result in excessive wear to the scraper blades, may cause damage tothe conveyor belt, and may cause the tip of the scraper blade to developan excessively high temperature due to the friction generated betweenthe scraper blade and the moving conveyor belt. If the scraper bladesare biased against the conveyor belt with too small of a force, thescraper blades may not effectively clean the conveyor belt.

In addition, the scraper blades may vibrate or chatter against theconveyor belt, thereby potentially damaging the conveyor belt cleanerand/or the belt, and decreasing cleaning efficiency. Scraper bladechatter may be caused by unevenness of the conveyor belt, such assagging of the belt, defects in the belt, or splices in the belt, and byfrictional forces generated between the scraper blade and the movingbelt. Chatter typically decreases as scraping pressure increases. Absentchatter, cleaning efficiency generally increases as scraping pressureincreases up to the limit where the belt cover strength is exceeded.Thus, the cleaning angle of the scraper blades and the force at whichthe scraper blades engage the conveyor belt effect vibration or chatterof the scraper blades against the conveyor belt cleaner as well as thecleaning efficiency.

Moreover, every primary and secondary apparatus has a design mass andtherefore a characteristic vibration frequency. The characteristicfrequency is affected by rotating or moving components such as the belt,gear boxes, motors plus changes that occur over time with the apparatussuch as quantity of bulk material conveyed or stored, wear and corrosionor by unwanted buildup of bulk solids in the form of fugitive materialssuch as carry back, spillage and dust. Changes in the characteristicfrequency of an apparatus can be an indication of a change in itsmechanical condition or its operating efficiency.

SUMMARY

A bulk material handling accessory such as a conveyor belt cleaner. Thebulk material handling accessory comprises a main frame adapted to beselectively rotatable about a first axis. The main frame comprises across shaft, a first mounting member attached to the cross shaft and asecond mounting member attached to the cross shaft. The first mountingmember may include one or more cradles, with each cradle including areceptacle. A pivot member is adapted to be located in the receptacle ofthe cradle. A scraping member is coupled to the pivot member such thatthe scraping member is pivotal with respect to the cross shaft about asecond axis. The scraping member includes an arm and a scraper bladeadapted to engage a conveyor belt. The arm of the scraping memberincludes a strut having a first end and a second end. The first end ofthe strut is adapted to be attached to the cross shaft by the pivotmember. The second end of the strut includes a mounting member having abracket, a retainer member and a slot formed between the bracket and theretainer member adapted to receive the scraper blade.

The bulk material handling apparatus also includes a damper mechanismhaving a first end coupled to the second mounting member of the mainframe and a second end coupled to the scraping member. The dampermechanism is adapted to bias the scraper blade into engagement with theconveyor belt and to dampen vibration of the scraper blade with respectto the conveyor belt. The damper mechanism includes a damper having afirst end coupled to the second mounting member and a second end coupledto the scraping member. The damper includes a piston and a housinghaving a fluid chamber. The piston is movable with respect to thehousing in response to movement of the scraper blade. The fluid chamberincludes a fluid such as magnetorheological fluid or electrorheologicalfluid. The viscosity of the fluid in the fluid chamber may beselectively changed to modify the damping characteristics of the damperin response to the operating conditions of the scraper blade by changinga magnetic field or an electric field that is applied to the fluid. Thedamping characteristics of the damper mechanism may be selectivelyvaried to accommodate changes in operating conditions.

One or more mounting mechanisms may be attached to the main frame. Eachmounting mechanism includes a linear positioning mechanism having afirst linear actuator and a support bracket, and a rotationalpositioning mechanism including a pivot arm and a second linearactuator. The support bracket couples the first linear actuator to thecross shaft. The first linear actuator is adapted to selectively movethe support bracket and the cross shaft along a generally lineartranslational axis. The pivot arm is attached to the cross shaft to themain frame and to the second linear actuator, such that the secondlinear actuator is adapted to selectively pivot the cross shaft aboutthe first axis.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention described herein is illustrated by way of example and notby way of limitation in the accompanying figures. For simplicity andclarity of illustration, elements illustrated in the figures are notnecessarily drawn to scale. For example, the dimensions of some elementsmay be exaggerated relative to other elements for clarity. Further,where considered appropriate, reference labels have been repeated amongthe figures to indicate corresponding or analogous elements.

FIG. 1 is a partially exploded view of a conveyor belt cleaner accordingto the present disclosure.

FIG. 2 is a partial perspective view of the conveyor belt cleaner ofFIG. 1.

FIG. 3 is a front elevation view of the cleaner mechanism of theconveyor belt cleaner.

FIG. 4 is a end view taken along line 4-4 of FIG. 3.

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 3.

FIG. 6 shows the conveyor belt cleaner as shown in FIG. 5 but with thedeflector shroud removed.

FIG. 7 shows the conveyor belt cleaner with a scraper blade inengagement with the conveyor belt at a positive rake cleaning angle.

FIG. 8 shows the conveyor belt cleaner with a scraper blade inengagement with the conveyor belt at a negative rake cleaning angle.

FIG. 9 is an exploded side elevation view of the conveyor belt cleaner.

FIG. 10 is a top view of the main frame of the conveyor belt cleaner.

FIG. 11 is a rear elevation view of the main frame.

FIG. 12 is a cross sectional view taken along line 12-12 of FIG. 11.

FIG. 13 is a top view of the upper mounting member of the main frame.

FIG. 14 is a front elevation view of the upper mounting member of themain frame.

FIG. 15 is an end view of the upper mounting member of the main frame.

FIG. 16 is a front elevation view of the center shaft of the main frame.

FIG. 17 is a bottom view of the center shaft.

FIG. 18 is an end view of the center shaft.

FIG. 19 is a front elevation view of the pivot shaft.

FIG. 20 is an end view of the pivot shaft.

FIG. 21 is a side elevation view of the pivot bushing.

FIG. 22 is a end view of the pivot bushing.

FIG. 23 is a top view of an end pivot cap.

FIG. 24 is a side elevation view of the end pivot cap.

FIG. 25 is a plan view of a center pivot cap.

FIG. 26 is a side elevation view of the center pivot cap.

FIG. 27 is a perspective view of the arm of the conveyor belt cleaner.

FIG. 28 is a top view of the arm.

FIG. 29 is a side elevation view of the arm.

FIG. 30 is a bottom view of the arm.

FIG. 31 is a rear elevation view of the arm.

FIG. 32 is a front elevation view of the arm.

FIG. 33 is a side elevation view of the scraper blade.

FIG. 34 is a front elevation view of the scraper blade of FIG. 33.

FIG. 35 is a cross sectional view of the damper.

FIG. 36 is a perspective view of the linear actuator mechanism of therotational positioning mechanism.

FIG. 37 is a side elevation view of the controller box.

FIG. 38 is a rear elevation view of the controller box.

FIG. 39 is a cross sectional view taken along line 39-39 of FIG. 37.

FIG. 40 is a perspective view of the deflector shroud.

FIG. 41 is a top view of the deflector shroud.

FIG. 42 is a side elevation view of the deflector shroud.

FIG. 43 is a rear elevation view of the deflector shroud.

FIG. 44 is a front elevation view of a mounting mechanism of theconveyor belt cleaner.

FIG. 45 is a side elevation view of the mounting mechanism.

FIG. 46 is a side elevation view of a support bracket of the mountingmechanism.

FIG. 47 is a cross sectional view taken along line 47-47 of FIG. 46.

FIG. 48 is a side elevation view of a bushing of the mounting mechanism.

FIG. 49 is a plan view of the bushing of the mounting mechanism.

FIG. 50 is an end view of the pivot arm.

FIG. 51 is a side elevation view of the pivot arm.

FIG. 52 is an end view of the adjustment collar,

FIG. 53 is a side elevation view of the adjustment collar.

FIG. 54 is a top plan view of the support bracket for the rotationalpositioning mechanism.

FIG. 55 is a side elevation view of the support bracket of FIG. 55.

FIG. 56 is a diagram illustrating the geometrical arrangement of thecleaner mechanism.

FIG. 57 is a block diagram illustrating a bulk material handling systemthat may utilize the conveyor belt cleaner depicted in FIGS. 1-56.

FIG. 58 is a block diagram illustrating a bulk material handlingcontroller of the bulk material handling system in regard to theconveyor belt cleaner depicted in FIGS. 1-56.

FIG. 59 is a block diagram illustrating a master controller of the bulkmaterial handling controller.

FIG. 60 is a block diagram illustrating an auxiliary controller of thebulk material handling controller.

FIGS. 61-64 show various status signal to control signal responsepatterns suitable for controlling bulk material handling accessoriessuch as a conveyor belt cleaner.

FIG. 65 is a flowchart of an embodiment of a method of configuringsystem parameters of the control signal patterns depicted in FIGS.61-64.

FIG. 66 depicts a flowchart of an embodiment of a safety response methodsuitable for a bulk material handling accessory such as a conveyor beltcleaner.

FIG. 67 depicts a graph showing bulk material loading effects on armdisplacement of a belt cleaner.

FIG. 68 depicts cable connections of an embodiment of a bulk materialhandling system.

DETAILED DESCRIPTION

The following description describes techniques of controllingaccessories for a bulk material handling system. In the followingdescription, numerous specific details such as logic implementations,opcodes, means to specify operands, resourcepartitioning/sharing/duplication implementations, types andinterrelationships of system components, and logicpartitioning/integration choices are set forth in order to provide amore thorough understanding of the present invention. It will beappreciated, however, by one skilled in the art that the invention maybe practiced without such specific details. In other instances, controlstructures, gate level circuits and full software instruction sequenceshave not been shown in detail in order not to obscure the invention.Those of ordinary skill in the art, with the included descriptions, willbe able to implement appropriate functionality without undueexperimentation.

References in the specification to “one embodiment”, “an embodiment”,“an example embodiment”, etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to effect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

Embodiments of the invention may be implemented in hardware, firmware,software, or any combination thereof. Embodiments of the invention mayalso be implemented as instructions stored on a machine-readable medium,which may be read and executed by one or more processors. Amachine-readable medium may include any mechanism for storing ortransmitting information in a form readable by a machine (e.g., acomputing device). For example, a machine-readable medium may includeread only memory (ROM); random access memory (RAM); magnetic diskstorage media; optical storage media; flash memory devices; and others.

Bulk Material Handling System

Referring now to FIG. 57, a bulk material handling system is depicted.The bulk material handling system may comprise a bulk material handlingapparatus 4, a bulk material handling accessory 6, and a user interface8. The bulk material handling apparatus 4 and bulk material handlingaccessory 6 may comprise various combinations of bulk material devices.For example, the bulk material handling apparatus 4 may comprise one ormore bins and the bulk material handling accessory 6 may comprise one ormore air cannons for moving the bulk material through, along or down thebins. Similarly, the bulk material handling apparatus 4 may comprise achute and the bulk material handling accessory 6 may comprise one ormore vibrators for moving the bulk material through, along or down thechute. Further, the bulk material handling apparatus 4 may comprise abulk material conveyor and the bulk material handling accessory 6 maycomprise a cleaner to scrape, peel, or otherwise clean a conveyor beltof the bulk material conveyor. Other combinations of bulk materialhandling apparatus and bulk material handling accessories arecontemplated.

The bulk material handling accessory 6 aids the bulk material handlingapparatus 4 in handling bulk material. For example, the bulk materialhandling accessory 6 may comprise cleaning blades that scrape, peel, orotherwise detach remnants of bulk material from a conveyor belt of thebulk material handling apparatus 4. In such an embodiment, the bulkmaterial handling accessory 6 aids the bulk material handling apparatus4 by preventing the bulk material from accumulating upon the conveyorbelt of the bulk material handling apparatus 4 and potentiallyobstructing movement of the conveyor belt through the bulk materialhandling apparatus 4.

The bulk material handling accessory 6 may comprise a controller 12 withsensors 10 for determining characteristic signals that can be related tothe operating characteristics of the bulk material handling accessory 6and/or the bulk material handling apparatus 4. The sensors 10 maycomprise motion sensors such as, for example, accelerometers to detectvibrations or other types of movement of the bulk material, the bulkmaterial handling apparatus 4, the bulk material handling accessory 6,and/or a component of either the bulk material handling apparatus 4 orone of its accessories 6. Further, the sensors 10 may comprisetemperature sensors such as, for example, infrared sensors to detect ormeasure temperature of the bulk material, the bulk material handlingapparatus 4, the bulk material handling accessory 6, and/or a componentof either the bulk material handling apparatus 4 or one of itsaccessories 6.

The controller 12 of the bulk material handling accessory 6 adjusts theoperation of the bulk material handling accessory 6 based upon thesignals of the sensors 10. Further, the controller 12 may receivesignals from the user interface 8 and may further adjust operation ofthe bulk material handling accessory 6 based upon the signals receivedfrom the user interface 8.

The user interface 8 may comprise various combinations of input/outputdevices such as, for example, LCD displays, LED displays, CRT monitors,flat panel displays, printers, keyboards, keys, buttons, mice, and thelike in order to present information to a user and receive input from auser. As depicted, the user interface 8 is coupled to the controller 12of the bulk material handling accessory 6. The coupling may beimplemented via wired and/or wireless technologies that enable the userinterface 8 to be positioned remotely from the bulk material handlingaccessory such as, for example, an RS-232, an RS-422, or an RS-485serial interface; an IEEE 802.3 (Ethernet) networking interface; an IEEE802.11 (WiFi) interface; and other interconnect technologies that permitremote positioning of the user interface 8. Similarly, the coupling maybe implemented via wired and/or wireless technologies that enable theuser interface 8 to be positioned nearby or locally to bulk materialhandling accessory such as, for example, Universal Serial Bus (USB)interconnects, IEEE 1394 (FireWire) interconnects, PS/2 mouse andkeyboard connectors, IEEE 802.15.1 (Bluetooth) interconnect, and otherinterconnect technologies that permit local positioning of the userinterface 8. While the above associates certain interconnecttechnologies with “remote” or “local” positioning of the user interface8, many of the above listed interconnect technologies are capable ofsupporting both “remote” and “local” user interfaces 40 despite beingbetter suited for one or the other. Further, the above listedinterconnect technologies are merely illustrative and some embodimentsmay utilize interconnect technologies not specifically listed above.

Further details of the bulk material handling system are presented belowin regard to an embodiment where the bulk material handling apparatus 4comprises a bulk material conveyor having a conveyor belt and where thebulk material handling accessory 6 comprises a conveyor belt cleanerwith cleaning blades. However, one skilled in the art should appreciatethat the following teachings in regard to the conveyor belt cleaner andconveyor belt embodiment are applicable to other embodiments of the bulkmaterial handling system such as a chute with vibrator embodiments and abin with air cannon embodiments.

Conveyor and Conveyor Belt Cleaner

FIGS. 1-56 depict mechanical aspects of an embodiment of the bulkmaterial handling system where the bulk material handling apparatus 4comprises a bulk material conveyor 78 comprising a conveyor belt 82having an outer load carrying surface 84 and where the bulk materialhandling accessory 6 comprises a conveyor belt cleaner 80. The conveyorbelt cleaner 80 may be a secondary conveyor belt cleaner as generallyshown in FIGS. 7 and 8 wherein the conveyor belt cleaner 80 is adaptedto scrape adherent material from the surface 84 of a portion of the belt82 that is moving in a generally linear direction as shown by thearrows. The conveyor belt cleaner of the present disclosure may also beused as a primary conveyor belt cleaner adapted to scrape material fromthe surface 84 of a portion of the belt 82 that is moving in arotational manner in engagement with the head pulley of the conveyor.Multiple primary and/or secondary conveyor belt cleaners can be used onthe same conveyor belt as operating conditions and requirements forcleaning dictate.

The conveyor belt cleaner 80 includes a cleaner mechanism 86 and one ormore mounting mechanisms 88A-B. The cleaner mechanism 86 includes a mainframe 92 including a cross shaft 94 having a generally linear centrallongitudinal axis 96. The cross shaft 94 extends generally linearlybetween a first end 98 and a second end 100. The cross shaft 94 mayinclude a single unitary member, or as shown in FIG. 1 the cross shaft94 may include a plurality of members or segments. As shown in FIG. 1,the cross shaft 94 includes a center shaft 102 extending between a firstend 104 and a second end 106. Mounting members 108, such as generallyplanar plates, including one or more peripheral apertures arerespectively attached to the first end 104 and the second end 106 of thecenter shaft 102. The cross shaft 94 also includes stub shafts 10A andB. Each stub shaft 110A-B extends between a first end 112 and a secondend 114. A respective mounting member 116, such as a generally planarplate, including one or more peripheral apertures is mounted to thefirst end 112 of each stub shaft 110A and B. The stub shaft 110A isadapted to be removably attached to the first end 104 of the centershaft 102 with fasteners, such as bolts and nuts, that extend throughthe apertures in the mounting members 108 and 116. The stub shaft 110Bis similarly adapted to be removably attached to the second end 106 ofthe center shaft 102 by fasteners that extend through the apertures inthe mounting members 108 and 116. The stub shaft 110A is adapted to beremovably mounted to the mounting mechanism 88A, and the stub shaft 110Bis adapted to be removably mounted to the mounting mechanism 88B. Thecenter shaft 102 and stub shafts 110A and B may be formed fromrectangular or square tubing as shown in FIG. 1, round tubing, solidmembers, or other structural components.

The center shaft 102 may have a different cross-sectional configurationor size, such as a different width, height, wall thickness and the like,than the stub shafts 110A and B. The stub shafts 110A and B may remain auniform size to facilitate mounting to the mounting mechanisms 88A-B,while the size of the center shaft 102 may be varied to take intoaccount particular operating conditions such as the width of theconveyor belt and thereby the length of the center shaft 102 between theends 104 and 106. Consequently, a smaller size center shaft 102 may beused with relatively narrow conveyor belts and a larger size centershaft 102 may be used in connection with wider conveyor belts tominimize deflection and to accommodate increased bending stresses. Theconnections between the stub shafts 110A-B and the center shaft 102 alsoenable the center shaft 102 to be removed from the stub shafts 110A andB while the stub shafts 110A-B remain mounted to the mounting mechanisms88A-B.

As shown in FIGS. 16-18, the center shaft 102 includes one or moregenerally circular apertures 118 extending through a first wall of thecenter shaft 102 and that are generally equally spaced apart from oneanother along the longitudinal length of the center shaft 102 betweenthe ends 104 and 106. The center shaft 102 also includes one or moreelongated slot-like apertures 120 that extend through a second side wallof the center shaft 102 and that are generally equally spaced apart fromone another along the longitudinal length of the center shaft 102between the ends 104 and 106. Each aperture 118 is associated with arespective aperture 120, such that each pair of apertures 118 and 120are located in the same position with respect to one another relative tothe length of the center shaft 102 between the ends 104 and 106. Theapertures 118 and 120 provide communication with a chamber 122 locatedwithin the center shaft 102. Each mounting member 108 and 116 includes alarge central aperture such that a hollow passageway extends through thecross shaft 94 from the first end 98 to the second end 100 and thatincludes the chamber 122.

As shown in FIG. 9, a plurality of cover plates 123 are removablyattached to the center shaft 102 such that each cover plate 123respectively covers a slot-like aperture 120. Each cover plate 123 maybe removed from the center shaft 102 to provide access to the chamber122 within the center shaft 102. A cord grip connector 124 oralternatively a grommet is respectively attached to the center shaft 102at each aperture 118.

The main frame 92 includes a lower mounting member 126, such as a bentplate, having a first end 128 connected to the wall of the center shaft102 that includes the slot-like apertures 120 and a second end 130located radially outwardly from the axis 96 with respect to the firstend 128. The lower mounting member 126 also extends longitudinallygenerally parallel to the axis 96 between a first end 132 and a secondend 134. The ends 132 and 134 extend outwardly slightly beyond thelocations of the slot-like apertures 120. The lower mounting member 126includes one or more mounting tabs 136 attached to the second end 130.Each mounting tab 136 includes an aperture 138 that extends through themounting tab 136 in a direction generally parallel to the axis 196. Themounting tabs 136 are generally uniformly spaced along the length of thelower mounting member 126 between the first end 132 and the second end134, with each mounting tab 136 in alignment with a respective aperture118 and slot-like aperture 120. Each of the apertures 138 in themounting tabs 136 is located generally concentrically about a generallylinear axis 140 that extends through each of the apertures 138. The axis140 is generally parallel to and spaced apart from the axis 96.

The main frame 92 also includes an upper mounting member 144 thatextends between a first end 146 and a second end 148 and that isattached to the center shaft 102. The upper mounting member 144 includesa base 150 that is connected to the center shaft 102 generallydiametrically from the lower mounting member 126 with respect to theaxis 96. The base 150 includes two outwardly extending legs 152 that aregenerally transverse to one another such that each leg 152 is adapted tobe attached to a respective wall of the tube that forms the center shaft102. The base 150 also includes a stem 154 that extends outwardly fromthe junction of the legs 152. The base 150 is thereby generallyY-shaped. The stem 154 is offset at an angle with respect to the legs152 such that the stem 154 is not disposed at an angle midway betweenthe legs 152.

A plurality of cradles 156 are attached to the outer end of the stem 154and are generally equidistantly spaced apart from one another along thelength of the stem 154 between the first end 146 and the second end 148of the upper mounting member 144. Each cradle 156 extends generallyparallel to the base 150 between a first end 158 and a second end 160.Each cradle 156 includes an open-top and open-end receptacle 162 formedby a generally semi-cylindrical interior wall 164. Each cradle 156 alsoincludes a pair of spaced apart and generally parallel flanges 166 thatextend from the first end 158 to the second end 160. The top surfaces ofthe flanges 166 are generally planar and generally coplanar with oneanother. Each flange 166 includes one or more apertures extendingtherethrough. The semi-cylindrical wall 164 of the cradle 156 is formedabout a generally linear axis 168. As shown in FIGS. 13 and 14, thereceptacles 162 located at each end 146 and 148 of the upper mountingmember 144 are approximately one-half the length of the receptacles 156located in the center of the upper mounting member 144 between the endcradles 156. Each flange 166 in the end cradles 156 includes oneaperture, whereas each flange 166 in the center cradles 156 includes twoapertures. The axis 168 extends generally parallel to the axis 96.

An end cap 172, as shown in FIGS. 23 and 24, is adapted to be removablyattached to each end cradle 156 that is located at the ends 146 and 148of the upper mounting member 144. The end cap 172 includes a open-bottomand open-end receptacle 174 formed by a semi-cylindrical interior wall176 extending about the axis 168. The end cap 172 includes a pair ofspaced apart and generally parallel flanges 178 each of which includesone or more apertures. The bottom surfaces of the flanges 178 aregenerally coplanar and are adapted to mate with the flanges 166 of theend cradles 156, such that the receptacle 162 of the cradle 156 andreceptacle 174 of the end cap 172 form a generally cylindricalreceptacle or bore that extends through the cradle 156 and end cap 172from the first end 158 to the second end 160 generally concentricallyabout and along the axis 168. The end caps 172 are removably attached tothe end cradles 156 by fasteners such as bolts and nuts.

A center cap 180, as shown in FIGS. 25 and 26, is adapted to beremovably attached to each center cradle 156 of the upper mountingmember 154. Each center cap 180 includes an open-bottom and open-endreceptacle 182 formed by a generally semi-cylindrical interior wall 184that extends about the axis 168. Each center cap 180 includes a pair ofspaced apart and generally parallel flanges 186, each of which includesa plurality of apertures. The bottom surfaces of the flanges 186 aregenerally coplanar with one another and are adapted to respectively matewith the top surfaces of the flanges 166 of the center cradles 156. Eachcenter cap 180 is adapted to be removably attached to a center cradle156 by fasteners, such as bolts and nuts, such that the receptacle 182of the center cap 180 and the receptacle 162 of the center cradle 156form a generally cylindrical receptacle or bore that extends through thecenter cradle 156 and center cap 180 from the first end 158 to thesecond end 160 concentrically about and along the axis 168. The mainframe 92, including the cross shaft 94, lower and upper mounting members126 and 144, the caps 172 and 180, and other components are preferablymade from corrosion resistant materials and may be made from metal suchas stainless steel.

The cleaner mechanism 86 includes one or more pivot shafts 190. Eachpivot shaft 190 extends between and is rotatably mounted to adjacentpairs of cradles 156 of the upper mounting member 144. The pivot shaft190 is generally cylindrical and extends concentrically about and alongthe axis 168 from a first end 192 to a second end 194. The pivot shaft190 includes a generally cylindrical surface 196. The pivot shaft 190 ispreferably made from a corrosion resistant material and may be made frommetal such as stainless steel.

Each end 192 and 194 of the pivot shaft 190 is adapted to be rotatablymounted to a respective cradle 156 by a bushing 200. The bushing 200 asshown in FIGS. 21 and 22 includes a generally cylindrical sleeve 202having a generally cylindrical outer surface, and a generally circularcollar 204 attached to one end of the sleeve 202. The collar 204 extendsoutwardly beyond the outer surface of the sleeve 202 thereby forming agenerally annular rim. A generally cylindrical bore 206 extends throughthe sleeve 202 and collar 204 along the axis 168. The bore 206 has adiameter such that the end of the pivot shaft 190 will closely fitwithin the bore 206 in rotating engagement with the inner wall of thebushing 200 formed by the bore 206. The bushing 200 may be formed from afriction reducing material and may be formed from metal such as oilitebronze.

The sleeve 202 of each bushing 200 is adapted to be located within thereceptacle 162 of a cradle 156 and is removably retained therein byclamping engagement with the end cap 172 or center cap 180. The collar204 of the bushing 200 is positioned adjacent the end of the receptacle162. The first end 192 of a pivot shaft 190 extends into the bore 206 ofa bushing 200 located in a first cradle 156, and the second end 194 ofthe pivot shaft 190 extends into the bore 206 of a bushing 200 locatedin an adjacent cradle 156. The pivot shaft 190 thereby extends between apair of adjacent cradles 156. The pivot shaft 190 is adapted to pivot orrotate about the central axis 168 with respect to the bushings 200 andcradle 156.

The cleaner mechanism 86 also includes one or more scraping members 210.Each scraping member 210 includes an arm 212 and a scraper blade 214.The arm 212 extends between a first end 216 and a second end 218 along acentral longitudinal axis 220. The first end 216 includes a generallycylindrical hub 222 that extends generally transversely to the axis 220between a first end 224 and a second end 226. A generally cylindricalbore 228 extends through the hub 222 from the first end 224 to thesecond end 226 along and concentrically about the axis 168. The pivotshaft 190 extends through the bore 228 of the hub 222 such that thefirst end 192 and second end 194 of the pivot shaft 190 each extendoutwardly beyond the ends 224 and 226 of the hub 222 approximately anequal distance. The generally cylindrical surface of the hub 222 formedby the bore 228 is sized to closely engage the surface 196 of the pivotshaft 190. The hub 222 may be coupled to the pivot shaft 190 such thatthe arm 212 and pivot shaft 190 conjointly pivot with one another aboutthe axis 168. The shaft 190 may be coupled to the hub 222 by a frictionfit therebetween or by a coupling member, such as a key or weld. Thepivot shaft 190 may also be integrally formed with the arm 212.Alternatively, the arm 212 may pivot with respect to the pivot shaft 190about the axis 168.

The arm 212 includes a strut 230 having a first end coupled to the hub222 and a second end coupled to a mounting member 232 that is located atthe second 218 of the arm 212. As viewed in plan, as shown in FIG. 28,the strut 230 extends generally linearly along the axis 220. As viewedin profile or elevation as shown in FIG. 29, the strut 230 is generallyS-shaped including a downwardly facing generally concavely curvedportion that extends from the hub 222, and an upwardly facing generallyconcavely curved portion that extends from the downwardly curved portionto the mounting member 232. The strut 230 includes a central ridge 234that extends from the hub 222 to the mounting member 232. Opposing sidewalls 236A-B extend downwardly and outwardly from the ridge 234 torespective lower edges 238A-B. Each lower edge 238A-B extends from thehub 222 to the mounting member 232. A channel 240 is located in thebottom wall of the strut 230 that extends from adjacent the hub 222 tothe mounting member 232. The channel 240 separates the bottom wall intorespective spaced apart first and second bottom wall portions 242A-B.The strut 230 includes a pair of spaced apart ribs 244A-B that extendalong respective bottom wall portions 242A-B, from a proximal endlocated adjacent the hub 232 to a distal end 246 located generally atthe bottom end of the upwardly facing concave portion of the strut 230and spaced apart from the second end 218 of the arm 212. Each rib 244A-Bincludes one or more apertures 248A-B, with each aperture 248A-B in eachrib 244A being aligned with a respective aperture 248A-B in the rib 244Bsuch that the apertures are located coaxially with respect to oneanother and generally parallel to the axis 168. The ribs 244A-B arelocated inwardly from, and generally parallel to, the edges 238A-B asshown in FIG. 30 to thereby form a lip between the ribs 244A-B and theedges 238A-B that extends along the bottom wall portions 242A-B. The arm212 includes a pair of spaced apart lugs 252A-B that are attached to andthat project downwardly and outwardly from the hub 222. A slot 254 islocated between the lugs 252A-B that extends parallel to the axis 168.The slot 254 is adapted to receive the stem 154 of the base 150 of theupper mounting member 144 of the main frame 92.

The mounting member 232 of the arm 212 includes a bracket 258 having abase attached to the second end of the strut 230. The bracket 258extends upwardly from the base to a tip 260. The bracket 258 includes aninterior surface 262 and a spaced apart exterior surface 264. Theinterior and exterior surfaces 262 and 264 are generally planar. Theinterior surface 262 is located in a plane that is generally parallel tothe axis 168. The interior surface 264 is located more closely adjacentto the first end 216 of the arm than the exterior surface 264. One ormore apertures 266 extend through the bracket 258 from the interiorsurface 262 to the exterior surface 264.

The mounting member 232 also includes a retainer member 270, such as anupwardly extending finger or ledge, that extends upwardly from thesecond end of the strut 230. The retainer member 270 is located inwardlyfrom the bracket 258, more closely toward the first end 216 of the arm212 than the bracket 258. The retainer member 270 extends upwardly to adistal tip 272. A transverse slot 274 extends through the mountingmember 232 between the bracket 258 and the retainer member 270. The slot274 is open at its top end between the tip 272 of the retainer member270 and the bracket 258, and at each end. The slot 272 forms an interiorwall on the retainer member 270 that is generally planar and parallel tothe interior surface 262 of the bracket 258. The slot 274 also forms abottom wall 276 that may be generally semi-circular as shown in FIG. 29,or that may be generally planar or other configurations if desired. Thetip 260 of the bracket 258 is located outwardly from the bottom wall 276of the slot 274 a distance further than the tip 272 of the retainermember 270 is located from the bottom wall 276. The length of theretainer member 270 is thereby shorter than the length of the bracket258. The arm 212 is preferably formed from corrosion resistant materialsand may be formed from metal, such as stainless steel.

The scraper blade 214 of the scraping member 210 is adapted to beremovably connected to the mounting member 232 of the arm 212.Alternatively, the scraper blade 214 may be integrally formed with thearm 212. As shown in FIGS. 33 and 34, the scraper blade 214 includes abase 280 having a bottom end 282 and a body 284 extending upwardly fromthe base 280 to a scraping edge 286. The scraper blade 214 includes aninterior surface 288 and a spaced apart exterior surface 290 each ofwhich extend from the bottom end 282 to the scraping edge 286, and froma first end 292 to a second end 294 of the scraper blade 214. As shownin FIG. 33, the interior surface 288 may be curved in a concavecylindrical manner, such as in the shape of a segment of a circle. Thesurfaces 288 and 290 are generally equally spaced apart from oneanother. The scraper blade 214 thereby has a generally uniform thicknessbetween the interior surface 288 and exterior surface 290. The base 280includes one or more apertures 296 that extend from the interior surface288 to the exterior surface 290 and that are adapted to align withrespective apertures 266 in the bracket 258 of the arm 212. The scraperblade 214 may be configured to provide a relatively constant scrapingangle with the conveyor belt 82 as the scraper blade 214 wears and ispivoted into continued engagement with the belt 82 about the axis 96.

The scraper blade 214 has a thickness such that the base 280 is adaptedto fit closely within the slot 274 of the mounting member 232 of the arm212 with the interior surface 288 of the base 280 located closelyadjacent the interior surface of the retainer member 270 and theexterior surface 290 located closely adjacent to the interior surface262 of the bracket 258. The bottom end 282 of the base 280 may be curvedin the form of a semi-circle to matingly engage the bottom wall 276 ofthe slot 274 in the mounting member 232. Alternatively, the bottom end282 of the base 280 may be generally planar, and the bottom wall 276 ofthe slot 274 may be planar, for mating engagement. The scraping edge 286of the scraper blade 214 may be rounded in the general shape of asemi-circle as shown in FIG. 33. Alternatively, the scraping edge 286may be generally planar. The scraping edge 286 may comprise a wear-intip as disclosed in U.S. Pat. No. 6,374,991 of Martin EngineeringCompany, which is incorporated herein by reference. The scraper blade214 is removably connected to the mounting member 232 of the arm 212 byfasteners that extend through the apertures 296 in the scraper blade 214and the apertures 266 in the bracket 258 of the mounting member 232. Thescraper blade 214 is thereby removable and replaceable on the arm 212,such as for example when the scraper blade 214 becomes worn or damaged.Each scraping member 210 is individually selectively removable andreplaceable on the main frame 92 by removal of the appropriate caps 172and 180.

The fasteners that connect the scraper blade 214 to the mounting member232 prevent transverse movement of the scraper blade 214 with respect tothe bracket 258. Frictional scraping forces applied to the scraping edge286 of the scraper blade 214 from engagement with the moving conveyorbelt 82 are resisted at least in part by engagement of the base 280 ofthe scraper blade 214 with the retainer member 270 of the mountingmember 232. A frictional scraping force applied to the scraping edge 286by the moving belt 82 presses the exterior surface 290 of the scraperblade 214 into engagement with the tip 260 of the bracket 258, and willattempt to pivot the bottom end 282 of the scraper blade 214 away fromthe interior surface 262 of the bracket 258, such that the scraper blade214 would pivot about the tip 260 of the bracket 258. However, thispivotal movement of the scraper blade 214 is prevented by engagement ofthe base 280 of the scraper blade 214 with the interior surface 288 ofthe retainer member 270 of the mounting member 232. The scraper blade214 may be formed from metal, such as stainless steel, and may includewear-resistant materials at the scraping edge 286 such as tungstencarbide or ceramic materials.

The cleaner mechanism 86 also includes one or more damper mechanisms302. Each damper mechanism 302 is associated with a respective scrapingmember 210. The damper mechanism 302 includes a first end 303 and asecond end 305. Each damper mechanism 302 includes a damper 304 and mayinclude a sensor enclosure or box 306. As shown in FIGS. 37-39, the box306 includes a generally rectangular housing 308 that forms one or moreinternal chambers 310. The box 306 also includes a removable andreplaceable generally planar side panel 312 on each side of the box 306.The side panels 312 are removably attached to the housing 308 to provideselective access to the chambers 310. The side panels 312 are attachedto the housing 308 in sealed engagement such that the box 306 issubstantially weather and water tight. An end wall of the housing 308includes an aperture 314 in communication with the chambers 310. A cordgrip member 316 is attached to the housing 308 in communication with theaperture 314 such that one or more electrical cords or cables may extendfrom a controller within the chambers 310 of the housing 308 to the cordgrip member 124 and chamber 122 of the main frame 92. The cord gripmember 316 maintains the box 306 water tight.

A mounting tab 320 is attached to the top of the housing 308 at thesecond end 305 of the damper mechanism 302. The mounting tab 320includes a bore 322 that extends therethrough along a central linearpivot axis 324. The mounting tab 320 has a width between opposing sidewalls at each end of the bore 322 that enables the mounting tab 320 tobe inserted between the ribs 244A-B of the arm 212, with the bore 322 incoaxial alignment with a respective pair of apertures 248A-B in each ofthe ribs 244A-B. A fastener, such as a bolt and nut, extends through theapertures 248 and bore 322 to thereby pivotally connect the dampermechanism 302 to the arm 212 such that the damper mechanism 302 and arm212 are pivotal with respect to one another about the pivot axis 324.The housing 308 also includes a mounting member 326 on the opposite sideof the housing 308 from the mounting member 320. The mounting member 326includes a threaded bore 328 that extends along a generally linear axis330 and that is in communication with the chambers 310.

The damper 304, as shown in FIG. 35, extends between a first end 334 anda second end 336. The damper 304 may comprise a combination gas springand damper, such as a magneto-rheological (MR) fluid damper, for examplethe Model RD-1119 MR fluid damper as manufactured by Lord Corporation.The damper 304 may be constructed and operate as generally disclosed inU.S. Pat. No. 5,277,281, which is incorporated herein by reference. Thedamper 304 includes a generally cylindrical and tubular housing 338forming an internal fluid chamber 340. The housing extends from a firstend 342 to a second end 344. A mounting member 346 is attached to thefirst end 342. A bore 348 extends through the mounting member 346 alongthe axis 140. The mounting member 346 may include a pair of spaced apartears through which the bore 348 extends, such that a mounting tab 136 ofthe lower mounting member 126 of the main frame 92 is adapted to bereceived between the ears, and such that a fastener may extend throughthe bore 348 of the mounting member 346 and through the aperture 138 ofthe mounting tab 136 such that the damper mechanism 302 is pivotal withrespect to the main frame 92 about the pivot axis 140.

A diaphragm 350 is located within the housing 338 and separates thefluid chamber 340 from an accumulator chamber 352 located at the secondend 334 of the housing 338. The accumulator chamber 352 may include apressurized gas, such as nitrogen. The fluid chamber 340 includes an MRfluid, such as a fluid consisting of carbonyl iron particles suspendedin silicone oil. The damper 304 includes a piston 354 having a pistonhead 355 located within the fluid chamber 340 and that includes a firstside 356 and a second side 358. The piston head 355 divides the fluidchamber 340 into sub-chambers respectively located on each side of thepiston head 355. The piston head 355 includes one or more fluid passages360 that extend through the piston head 355 between the first and secondsides 356 and 358 which place the sub-chambers of the fluid chamber 340in fluid communication with one another. Fluid passages may also beformed between the edge of the piston head 355 and the internal sidewall of the housing 338 if desired. The piston 354 includes anelectrical coil 362 wrapped around the piston head 355. The piston head355 is made of a magnetically permeable material.

The piston 354 includes a generally tubular shaft 364 having a first end366 connected to the piston head 355 and a second end 368 that isthreaded and located externally of the housing 308. The second end 368of the shaft 364 is adapted to be inserted into the threaded bore 328for rigid connection to the mounting member 326 of the control box 306.The shaft 364 extends concentrically about and along a linear axis 330.The shaft 364 extends through the second end 344 of the housing 338 andis sealed fluid tight thereto with a seal 370. Electrical wires extendfrom the electrical coil 362 through the central bore within the shaft364 and outwardly from the second end 368, through the bore 328 and intochamber 310 of the box 306 for connection to an auxiliary controller305.

The piston 354 is linearly slideable along the axis 330 with respect tothe housing 338 in each direction along the axis 330. As the piston 354moves along the axis 330 with respect to the housing 338 MR fluid willflow from a first sub-chamber to a second sub-chamber through the fluidpassages 360 to thereby allow sliding movement of the piston 354 withrespect to the housing 338. The accumulator 352 accommodates MR fluiddisplaced by the insertion of the shaft 364 into the fluid chamber 340and thermal expansion of the MR fluid. Selected variation in themagnetic flux generated by the electrical coil 362 provides acorresponding change in the flow characteristics of the MR fluid. MRfluids are able to change stiffness or viscosity over a very largerange. Controlling the flow characteristics of the MR fluid therebyprovides control over the ability of the piston 354 to move along theaxis 330 with respect to the housing 338 and to thereby dampenvibrations resulting from vibratory forces applied to the piston 354.Kinetic energy from the moving conveyor belt 82 is transferred to thedamper 304 through the scraping member 210. The MR fluid in the damperconverts the kinetic energy into heat and transfers the heat to theatmosphere. The damper 304 provides a relatively constant transfer ofaxial force between the first end 334 and second end 336 regardless ofthe displacement of the piston 354 with respect to the housing 338, andwhile dampening vibration of the scraper blade 214 with respect to thebelt 82. While the control box 306 is shown in the drawings asconnecting the second end 368 of the piston 354 to the arm 212, ifdesired, the second end 368 of the piston 354 may be pivotally connecteddirectly to the arm 212.

The scraping force with which each scraper blade 214 is biased intoengagement with the conveyor belt 82 is provided by the damper 304.Different pressures of the gas in the accumulator chamber 352, anddifferent volumes of the accumulator chamber 352, will provide differentforce versus displacement output curves. A damper 304 with a largeaccumulator chamber 352 volume and a short piston stroke is preferredsuch that the output force versus displacement curve is relatively flat,whereby a relatively constant scraping force and cleaning pressure isprovided between the scraper blade 214 and the belt 82. Different typesof dampers 304, with different gas pressures and/or differentaccumulator chamber volumes, can be used as desired to provide a desiredscraping force and scraping pressure. The different types of dampers 304can be exchanged with one another in the cleaner mechanism 86 toselectively change the scraping force with which the scraper blades 214engage the belt 82.

As stated above, the dampers 304 comprise magnetorheological (MR) fluiddampers that contain MR fluid. The MR fluid has a viscosity that isdependent upon a magnetic field, thus the dampening effect of the MRdamper may be adjusted by adjusting the magnetic field applied to the MRfluid. In another embodiment, the dampers 304 compriseelectrorheological (ER) dampers that contain ER fluid. Similar to the MRfluid, the ER fluid has a viscosity that is dependent upon an electricfield, thus the dampening effect of the ER damper may be adjusted byadjusting the electric field applied to the ER fluid. While someembodiments utilize MR fluid dampers or ER fluid dampers, those skilledin the art should appreciate that the dampers 304 may comprise othertypes of controlled dampers to achieve the desired controlled dampeningeffect. If desired the damper 304 may include a resilient biasingmember, such as a mechanical coil spring, that extends around thehousing 338 and piston 354 with a first end of the biasing membercoupled to the housing 338 and a second end coupled to the piston 354.

The lugs 252A and B of the arm 212 are adapted to engage the stem 154 ofthe upper mounting member 144 to limit pivotal movement of the arm 212about the pivot axis 168. The lugs 252A-B thereby limit the possiblelength of stroke of the piston 354 of the damper 304, preventingover-retraction of the piston 354 which could damage the diaphragm 350and preventing over-extension of the piston 354 which could damage theseal 370.

The upper mounting member 144 is designed so that the scraper blades 214can be either in-line, or offset and overlapping. As shown in FIG. 1,all of the scraper blades 214 are located in-line with one another. Ifdesired, the upper mounting member 144 of the main frame 92 may bedivided into a plurality of segments wherein each segment includes afirst and second cradle 156 respectively at each end. Every othermounting member segment is reversed end for end to facilitate an offsetand overlapping scraper blade arrangement. Due to the offset of thestems 154, the cradles 156 of every other mounting segment will bealigned with one another, with one set of cradles being aligned alongthe pivot axis 168 and a second set of cradles 156 being aligned along aparallel pivot axis that is spaced apart from and parallel to the pivotaxis 168. The parallel pivot axes may be offset from one another aselected distance such as, for example, twenty-five millimeters. A firstset of every other scraping members 210 will thereby be aligned with oneanother, while a second set of the remaining scraping members 210 willbe aligned with one another. The scraper blades 214 of adjacent scrapingmembers 210 are thereby offset with one another, such that the scraperblades 214 may overlap one another along the width of the belt. Thewidth of the scraper blades used in the offset position are preferablywider than the width of the scraper blades used in the in-line positionto provide overlapping of adjacent scraper blades. Alternatively, thecradles 156 can be divided, with end caps 172 used in place of centercaps 180, and the spacing of the individual mounting members 144 can belocated closer to one another to provide overlapping of adjacent scraperblades. The damper mechanisms 302 are pivotally connected to theapertures 248A of the first set of aligned scraping members 210, and thedamper mechanisms 302 are pivotally connected to the apertures 248B ofthe second set of aligned scraping members 210.

When the scraping members 210 are configured in an offset andoverlapping arrangement, the scraper blade 214 of each scraping member210 may be pivotally mounted to the mounting member 232, such as by asingle fastener extending through an aperture 226 and an aperture 296,such that the scraper blade 214 is pivotal with respect to the arm 212about a pivot axis that is generally transverse to the axis 168. Thebottom end 282 of the blade 214 is spaced apart from the bottom wall 276of the slot 274 in the retainer member 270 when the blade 214 is in acentered position, such that the blade 214 can pivot in either directionabout the pivot axis such as, for example, plus or minus five degreesbefore the base 280 of the blade 214 engages the bottom wall 276 of theslot 274. In this configuration, a wear-in tip should additionally beprovided at the corners formed by the scraping edge 286 and the ends 292and 294 of the blade 214 to prevent gouging of the belt 82 as the blade214 adapts to the belt surface 84.

The cleaner mechanism 86 also includes a deflector shroud 374. As shownin FIGS. 40-45, the deflector shroud 374 includes a first side wall 376and a mirror-image second side wall 378. The first and second side walls376 and 378 are spaced apart and generally parallel to one another, andextend between a front wall 380 and a rear wall 382. The first andsecond side walls 376 and 378 also each extend between a lower edge 384and an upper edge 386. A passageway extends through the deflector shroud374 from an opening formed in the top end of the deflector shroud 374between the upper edges 376 of the first and second sidewalls 376 and378 to an opening formed in the bottom end of the deflector shroud 374between the lower edges 384 of the first and second side walls 376 and378. Each side wall 376 and 378 includes a pocket 388 adapted to receivethe damper 304 therebetween.

As shown in FIGS. 4 and 5, the damper mechanism 302 extends through thepassageway in the deflector shroud 374 with the damper 304 located inthe pockets 388. The upper edge 386 of the first and second side walls376 and 378 matingly engage the edges 238A-B of the strut 230 of thescraper member 210 to form a seal therebetween. The deflector shroud 374thereby substantially encloses the damper mechanism 302, and totallyencloses the box 306 and the upper end of the damper 304, to preventmaterial scraped from the belt 82 by the scraper blade 214 fromimpacting on or engaging these components. The deflector shroud 374 maybe made from an elastomeric material, such as urethane.

The mounting mechanisms 88A-B may be constructed generally asmirror-images of one another. The mounting mechanism 88B is shown inFIGS. 44 and 45. Each mounting mechanism 88A-B includes a linearpositioning mechanism 394 having a lower mounting bracket 396 and anupper mounting bracket 398, such as angle irons. A vertical leg of themounting brackets 396 and 398 includes apertures such that the verticalleg is adapted to be removably attached to a stationary supportstructure. Each horizontal leg of the mounting brackets 396 and 398includes an aperture. A linear actuator such as a threaded rod or shaft400 having a central linear axis 402 extends between the lower and uppermounting brackets 396 and 398 and through the apertures in thehorizontal legs thereof. A pair of support nuts 404 are threadablyattached to the shaft 404, with a respective support nut 404 engagingthe top surface of the horizontal leg of the mounting brackets 396 and398. A pair of locking nuts 406 are threadably engaged to the shaft 404,with a respective locking nut 406 being located adjacent the bottomsurface of a respective horizontal leg of each of the mounting brackets396 and 398. The locking nuts 406 may be selectively moved away from themounting brackets 396 and 398 such that the shaft 404 is selectivelyrotatable about the axis 402 in either a clockwise or counter-clockwisedirection as desired. The locking nuts 406 may be engaged against themounting brackets 396 and 398 to thereby prevent rotation of the shaft400 about the axis 402. The linear actuator 400 may alternativelycomprise an electrical, hydraulic or pneumatic actuator respectivelypositioned at each end of the main frame 92.

The linear positioning mechanism 394 also includes a support bracket410. The support bracket 410 includes a generally linear bore 412 thatextends from the bottom end to the top end of the support bracket 410and that is adapted to receive the threaded shaft 400. The supportbracket 410 also includes a passageway 414 that extends generallyhorizontally and transversely to the bore 412 through the supportbracket 410 between opposite side walls. The passageway 414 includes agenerally circular and concave receptacle 416 that is adapted to receivea generally circular bushing 418. The bushing 418 includes a generallycircular and convex outer wall 420 that is adapted to rotatably engageand mate with the receptacle 416. The bushing 418 also includes acentral bore 422 that is adapted to receive and matingly engage a stubshaft 110A or B of the main frame 92 such that the main frame 92 and thebushing 418 are conjointly rotatable about the axis 96 with respect tothe support bracket 410. The support brackets 410 of the mountingmechanisms 88A-B respectively receive and support the opposing ends ofthe main frame 92 within the bushings 418. The support brackets 410 andthe cleaner mechanism 86 are selectively moveable in a generally lineardirection along the axis 402 of the shafts 400 in either direction,upwardly or downwardly, by appropriate lifting or lowering of thethreaded shafts 400 about their respective axes 402 by means of nuts456. If desired electrically operated rotational actuators may beoperatively coupled to each shaft 400 to provide selected rotation ofthe shafts 400 and thereby selective positioning of the cleanermechanism 86. Shaft 401 may be keyed to bore 412 to limit horizontalshifting of the assembly 80 relative to the cross axis of conveyor belt82.

One or both mounting mechanisms 88A-B may include a rotationalpositioning mechanism 428. The rotational positioning mechanism 428includes a collar 430, such as a generally planar plate, including acentral aperture 432 adapted to matingly receive a stub shaft 110A or Bsuch that the collar 430 and the main frame 92 are conjointly rotatablewith one another about the axis 96. The collar 430 also includes aplurality of peripheral apertures and arcuate slots 434. The rotationalpositioning mechanism 428 also includes a pivot arm 436. The first end438 of the pivot arm 436 includes a generally circular central aperture442 adapted to receive the stub shaft 110A or B of the main frame 92.The first end 438 also includes a plurality of peripheral apertures 444spaced in a generally uniform manner about the central aperture 442. Thefirst end 438 of the pivot arm 436 is adapted to be removably connectedto the collar 430 by fasteners that respectively extend through theperipheral apertures 434 and 444. The position of the pivot arm 436 withrespect to the collar 430 about the axis 96 may be adjusted byselectively placing the fasteners within the slotted apertures 434 ofthe collar 430. The second end 440 of the pivot arm 436 includes anaperture 446 that is spaced apart from the central aperture 442.

The rotational positioning mechanism 428 also includes a support bracket450 having a bore 452 adapted to threadably receive the threaded shaft400 such that the support bracket 450 is located on shaft 402 by meansof nuts 456 and supported by the shaft 400. The support bracket 450 alsoincludes a longitudinal threaded bore 452 extending inwardly into thesupport bracket 450 generally transversely to the central axis of thethreaded bore 452. The support bracket 450 is threadably attached to thethreaded shaft 400 spaced apart from and below the bottom of the supportbracket 410 of the linear positioning mechanism 394. The central axis ofthe threaded bore 454 extends generally perpendicular to the axis 402.One or more locking nuts 456 are threadably engaged to the shaft 400 andare located above and below the support bracket 410 and the supportbracket 450 to selectively lock the brackets in place with respect tothe threaded shaft 400.

The rotational positioning mechanism 428 also includes a linear actuatormechanism 460. The linear actuator mechanism 460 includes a fluidcylinder 462 having a first end 464 and a second end 466. The fluidcylinder 462 includes a housing 468 having an aperture 470 at the secondend 466. The aperture 470 extends along a generally linear axis 472. Anextendable and retractable linear ram 474 extends outwardly from thefirst end of the housing 468 to a distal end 476 having an aperture 478.The aperture 478 extends along an axis 480 that is parallel to andspaced apart from the axis 472. The ram 474 extends along a centrallongitudinal axis 482 that extends from the first end 464 to the secondend 466 of the fluid cylinder 462. The longitudinal axis 482 isperpendicular to the axes 472 and 480.

The second end 466 of the fluid cylinder 462 is pivotally attached tothe support bracket 450 by a fastener that extends through the aperture470 and into the threaded bore 454 of the support bracket 450. The fluidcylinder 464 is thereby pivotal with respect to the support bracket 450about the axis 474. The first end 464 of the fluid cylinder 462, andthereby the distal end 476 of the ram 474, is pivotally attached to thesecond end 440 of the pivot arm 436 by a fastener that extends throughthe aperture 478 and the aperture 446. The fluid cylinder 462 is therebypivotal with respect to the pivot arm 436 about the axis 480. The distalend 476 of the ram 474 may be selectively moved in either direction,extended or retracted, with respect to the housing 462 along the axis482 with respect to the housing 462.

The linear actuator mechanism 460 also includes an electrical motoroperatively connected to a fluid pump 484 that is in fluid communicationwith the fluid cylinder 462. The electrical motor is in electricalcommunication with the auxiliary controllers 305 in the control boxes306. The fluid pump 484 provides for the selective extension andretraction of the ram 474. The fluid cylinder 462 and fluid pump 484 maybe hydraulically operated, or if desired may be pneumatically operated.The linear actuator mechanism 460 may be operated on direct current (DC)voltage, such as at twenty-four volts DC. The linear actuator mechanism460 may be the Mini Motion Package actuator as manufactured by KYBCorporation.

As viewed in FIG. 45, simultaneous extension of the rams 474 of thelinear actuator mechanisms 460 of the mounting mechanisms 88A-B willpivot or rotate the pivot arms 436 and the cleaner mechanism 86 in acounter-clockwise direction about the axis 96. Retraction of the rams474 will pivot the pivot arms 436 and cleaner mechanism 86 in aclockwise direction about the axis 96. Whether one or both of themounting mechanisms 88A and B include a rotational positioning mechanism428 may be determined based on the force output of the linear actuatormechanism 460 and the width of the conveyor belt 82. For example, onlyone mounting mechanism 88A or B may include a rotational positioningmechanism 428 when used in connection with belts up to approximately1200 millimeters (48 inches) wide, whereas both mounting mechanisms 88Aand B may include respective rotational positioning mechanisms 460 whenused in connection with wider belts.

As shown in FIG. 7, the scraper blade 214 is disposed at a positivecleaning or rake angle of approximately forty-five degrees with respectto the surface 84 of the conveyor belt 82. A positive cleaning or rakeangle, also known as a peeling angle, is one wherein the scraper bladeis slanted into the direction of travel of the conveyor belt. As shownin FIG. 8, the scraper blade 14 is disposed at a negative cleaning orrake angle of approximately minus ten degrees with respect to thesurface 84 of the conveyor belt 82. A negative cleaning or rake angle,also known as a scraping angle, is one wherein the scraper blade isslanted in the same direction as the direction of belt travel. A zerorake cleaning angle is one where the scraper blade is perpendicular tothe surface of the belt 82.

The cleaning angle of the cleaner mechanism 86 can be varied as desiredbetween the aforementioned cleaning angles by changing the mountingdistance between the rotational axis 96 of the main frame 92 and thesurface 84 of the conveyor belt 82. Appropriate rotation of the shafts400 of the mounting mechanisms 88A-B move the pivot axis 96 of thecleaner mechanism 86 along a plane 488 that is generally parallel to thecentral axes 402 of the shafts 400 toward the surface of the conveyorbelt 82. When the shafts 400 are rotated in an opposite direction, thepivot axis 96 of the cleaner mechanism 86 will move along the plane 488in an opposite direction away from the surface of the conveyor belt 82.The linear positioning mechanism 394 thereby allows selective placementof the pivot axis 96 of the cleaner mechanism 86 along the plane 488,such that the scraper blades 214 engage the surface 84 of the conveyorbelt 82 at a desired cleaning angle, such as anywhere between a positiverake cleaning angle of forty-five degrees to a negative rake cleaningangle of minus ten degrees. Other ranges of cleaning angles may be usedas desired. The cleaning angle of the scraper blades 214 can be adjustedafter installation of the conveyor belt cleaner 80 to fine tune thecleaning angle to an optimal cleaning angle, and to change the cleaningangle as may be needed due to changes in belt speed, changes in theconveyed material, or changes in other operational parameters. Suchadjustment can be done manually or automatically.

Once the cleaner mechanism 86 is located in its desired mountingposition along the plane 488, the linear actuator mechanism 460 of therotational positioning mechanism 48 rotates the cleaner mechanism 86about the axis 96. Extension of the ram 474 of the fluid cylinder 462will pivot the pivot arm 436 and the cleaner mechanism 86 in acounter-clockwise direction, as viewed in FIGS. 7 and 45, to rotate thescraper blades 214 into engagement with the conveyor belt 82 such thatthe dampers 304 resiliently bias their respective scraper blades 214into engagement with the surface of the conveyor belt 82 with a desiredamount of force and scraping pressure.

Retraction of the ram 474 of the fluid cylinder 462 will pivot the pivotarm 436 and cleaner mechanism 86 in a clockwise direction as viewed inFIGS. 7 and 45 and thereby disengages the scraper blades 214 from theconveyor belt 82. The rotational positioning mechanism 428 may therebydisengage the cleaner mechanism 86 from the conveyor belt 82 when thebelt 82 reverses its direction of travel, or for purposes ofmaintenance. The linear actuator mechanisms 460 of the rotationalpositioning mechanisms 48 will rotate the scraper blades 214 about theaxis 96 into continuing scraping engagement with the belt 82 as thescraper blades 214 wear during use while maintaining a substantiallyconstant cleaning angle and cleaning pressure. Position indicatingsensors such as magnetic switches may be used to limit the travel of arm436.

Each damper 304 respectively dampens vibration of its associated scraperblade 214 with respect to the conveyor belt 82 during operation. Eachdamper 304 is individually controlled by a respective auxiliarycontroller 305 in its associated box 306, such that dampening of eachscraper blade 214 can be individually controlled. The dampeningcharacteristics of each damper 304 may be varied during operation of theconveyor belt cleaner 80 to accommodate changes in operating conditions.The operating condition of the accessory bulk material handlingapparatus, such as the conveyor belt cleaner 80, air cannon, orindustrial vibrator, and the operating condition of the combination ofthese accessory apparatus with a primary bulk material handlingapparatus, is determined by sensing and monitoring the vibration emittedby the combination of the accessory and primary apparatus. Changes inthe emitted vibration are used to initiate control of the accessoryapparatus, such that the combination of the accessory apparatus and theprimary apparatus will operate at an optimum level of performance.

The geometrical arrangement of the cleaner mechanism 86 is generallyillustrated in FIG. 56 in connection with an X-Y rectangular coordinatesystem. The geometrical arrangement of the cleaner mechanism 86 enablesthe cleaner mechanism 86 to be used with the scraper blades 214 inengagement with the belt 82 at positive, zero, or negative rake cleaningangles “CA”. If the axis that determines the arc and bias of the scraperblades 214 was located coaxial with the axis 168, the cleaner mechanism86 could only be used at positive rake cleaning angles, because raisingthe cleaner mechanism 86 along the plane 488 for operation at a zero ornegative rake cleaning angle would create an interference between thearm 212 and the belt 82 unless the scraper blade engages the belt on thearc of a pulley. As shown in FIG. 56, a virtual pivot axis 490 isprovided that defines the curvature and bias angle of the scraper blade214. The virtual pivot axis 490 is spaced apart from and parallel to thepivot axis 168 and is located above the pivot axis 168 between the pivotaxis 168 and the belt 82. If the virtual pivot axis 490 was located onthe pivot axis 168, the bias angle of the scraper blade 214 would beninety degrees and would provide a constant cleaning angle during wear.When the virtual pivot axis 490 is located above the axis 168 the biasangle of the blade 214 is less than ninety degrees and the cleaningangle remains approximately constant (±5%) during wear using a scraperblade 214 formed in an arc of a circle about the axis 490. Regardless ofthe mounting height of the belt cleaner mechanism 86 along the plane488, or the degree of rotation of the belt cleaner mechanism 86 aboutthe axis 96, the geometrical arrangement of the belt cleaner mechanism86 will maintain a substantially constant cleaning angle between thescraper blades 214 and the belt 82.

Bulk Material Handling Controller

Referring now to FIGS. 58-60, one embodiment of the bulk materialhandling controller 12 will be described. As depicted, the controller 12comprises a master controller 500 and one or more auxiliary controllers305. While the controller 12 may be implemented in a distributed manneras shown in FIGS. 58-60, other embodiments may comprise a singlecontroller 500 without separate auxiliary controllers 305. In such anembodiment, the sensors of the auxiliary controller 305 may bemaintained with or near the components being monitored but the logicalcomponents (e.g. processors) of the auxiliary controller 305 may beeliminated with the single controller 500 configured to perform thelogical tasks of both the master controller and the of auxiliarycontrollers. In yet another embodiment, the bulk material handlingcontroller 12 may comprise only auxiliary controllers 305 without havinga separate master controller 500. In such an embodiment, the tasks ofthe master controller 500 may be distributed among the auxiliarycontroller 305, assigned to a single auxiliary controller 305, and/orsome tasks of the master controller 500 may be eliminated. Further, toaid one skilled in the art in understanding the construction and theoperation of the bulk material handling controller 12, the controller 12is described below in the context of controlling the belt cleanermechanism 86. However, those skilled in the art should appreciate thatthe teachings regarding the bulk material handling controller 12 may bereadily applied to other bulk material handling apparatus 4 and/or otherbulk material handling accessories 6.

Referring now to FIG. 58, the relationship between components of thebulk material handling controller 12 and components of a bulk materialhandling accessory such as the belt cleaner mechanism 86 are depicted.As depicted, the master controller 500 is coupled to positioningmechanisms 510 of the belt cleaner mechanism 86 such as, for example,the linear positioning mechanism 394 and the rotational positioningmechanism 428. As such, the master controller 500, in one embodiment,may generate control signals to adjust the positioning of the bulkmaterial handling accessory 6 in relation to the bulk material handler4. For example, the master controller 500 may generate control signalsthat cause the linear positioning mechanism 394 to move belt cleanermechanism 86 closer to the conveyor belt 82 or may generate controlsignals that cause the linear positioning mechanism 394 to move the beltcleaner mechanism 86 further from the conveyor belt 82. Similarly, themaster controller 500 may generate control signals that cause therotational positioning mechanism 428 to rotate the belt cleanermechanism 86 in relation to the conveyor belt 82. Via control signals tothe linear positioning mechanism 394 and the rotational positioningmechanism 428, the master controller 510 may adjust the force exerted bythe scrapper blades 214 upon the belt 82 as well as adjust the angle atwhich the scrapper blades 214 contact the belt 82.

Each auxiliary controller 305 controls one or more aspects of the bulkmaterial handling accessory 6. In one embodiment, each arm 212 comprisesan auxiliary controller 305 that generates control signals which causerespective dampers 304 to controllably dampen vibrations of itsassociated arm 212. In one embodiment, the auxiliary controller 305generates the control signal based upon signals received from itssensors such as the accelerometers 502 and the temperature sensor 504.As explained above, the dampers 304 have a controllable dampening ratethat is linear with respect to the control signals received from theauxiliary controller 305. Thus, the auxiliary controllers 305 in oneembodiment may increase the dampening effect of its damper 304 byincreasing the current of the control signal to the damper 304 and maydecrease the dampening effect of its damper 304 by decreasing thecurrent of the control signal to the damper 304. However, otherembodiments may utilize dampers 304 that have controllable dampeningrates that are non-linear with respect to the received control signals,and the auxiliary controllers 305 may generate the control signals toaccount for the non-linear dampening rates.

A master supply block 520 is also depicted in FIG. 58. In oneembodiment, the master supply block 520 receives a power signal from amain power source and conditions and/or transforms the received powersignal to provide the controller 12 and accessory 6 with appropriatepower signals. In one embodiment, the main power source supplies themaster supply block 520 with and AC power signal and the main supplyblock 520 transforms the received AC power signal into one or more DCpower signals that are suitable for the bulk material handlingcontroller 12 and the bulk material handling accessory 6.

The master supply block 520 may further generate a status signal whichmay be used to provide the master controller 500 with statusinformation. In one embodiment, the master supply block 520 may generatea status signal to inform the master controller 500 of a power failuresuch as, for example, the master supply block 520 receiving inadequatepower from its main power source and/or the master supply block 520providing inadequate power to components of the bulk material handlingsystem. Moreover, the master supply block 520 may comprise an alternatepower source or power reserve such as, for example, high power batteriesor supercapacitors that are capable of supplying sufficient power forthe bulk material handling controller 12 and bulk material handlingaccessory 6 to execute a fail response in response to the status signalinforming the master controller 500 of a failure of its main powersource. For example, the power reserves of the master supply block 520may provide sufficient power for the controller 12 and accessory 6 tosafely respond to a situation wherein the main power source provides nopower (e.g. black out) or insufficient power (e.g. brown out). In oneembodiment, the master controller 500 may generate control signals thatresult in the positioning mechanisms 510 retracting the arms 212 fromthe belt 82 in order to prevent the arms 212 from damaging the belt 82if the master supply block 520 is unable to supply sufficient power tooperate the accessory 6.

Further details regarding cable connections between components of thebulk material handling controller 12 and components of a bulk materialhandling accessory such as the belt cleaner mechanism 86 are depicted inFIG. 68. As shown, each auxiliary controller 305 may be coupled to aconnection box 590 via ten (10) 18-gauge cables and each rotationalpositioning mechanism 428 of the positioning mechanisms 530 may becoupled to the connection box 590 via three (3) 14-gauge cables. Themaster controller 500 may be coupled to a linear positioning mechanism396 of the positioning mechanisms 530 by three (3) 14-gauge cables andto a power plug by three (3) 18-gauge cables. The master controller 500may be further connected to the auxiliary controllers 305 via ten (10)18-gauge cables that connect the master controller 500 to the connectionbox 590, and to the rotational positioning mechanisms 428 via five (5)14-gauge cables that connect the master controller 500 to the connectionbox. The connection box 590 appropriately interconnects the cables ofthe master controller 500 with the cables of the auxiliary controllers305 and the rotational positioning mechanisms 428 and thus provides acentral location for interconnecting such components.

FIG. 59 depicts additional details regarding an embodiment of the mastercontroller 500. As depicted, the master controller 500 in one embodimentcomprises a processor 540, a memory 542, one or more I/O interfaces 544,and a real time clock 546. The processor 540 generally manages the othercomponents of the master controller 500. To this end, the processor 540in one embodiment comprises embedded firmware which the processor 540executes to perform various tasks. The processor 540 may be implementedusing a general purpose processor, a digital signal processor, or amicrocontroller which are available from numerous manufactures such asIntel Corporation, Advanced Micro Device, International BusinessMachines, Texas Instruments, or the like. In one embodiment, theprocessor 540 comprises either TMS320LF2407 or TMS320F2806 digitalsignal processor marketed by Texas Instruments though other processorsmay be used.

The memory 542 stores data for the master controller 500. In particular,the processor 540 may read data from the memory 542 and write data tothe memory 542. In one embodiment, the memory 542 comprises a removablememory card having a capacity of at least 512 kilobytes. In such anembodiment, the memory card may be removed in order to archive itsstored data for future reference and/or may be removed for analysis byanother computing device.

The one or more I/O interfaces 544 provide the processor 540 withinterfaces for exchanging data with external devices such as the userinterface 8, the auxiliary controllers 305, and the positioningmechanisms 510. In one embodiment, the auxiliary interface 544 comprisesan RS-485 serial interface which couples the master controller 500 tothe auxiliary controllers 305 in a daisy chain manner. The auxiliaryinterface 305 may further comprise other wired and/or wireless interfacethat may be used to operatively couple the user interface 8, theauxiliary controllers 305, and the positioning mechanisms 510 to themaster controller 500. Such wired and/or wireless interfaces may includebut are not limited to the following: RS-232, RS-422, RS-485 andController Area Network (CAN) serial interfaces; IEEE 802.3 (Ethernet)networking interfaces; IEEE 802.11 (WiFi) interfaces; Universal SerialBus (USB) interfaces; IEEE 1394 (FireWire) interfaces; PS/2 mouse andkeyboard interfaces; and IEEE 802.15.1 (Bluetooth) interfaces.

The real time clock 546 provides the processor 540 with a current timereference. The processor 540 may utilize the current time reference totime stamp data received from devices coupled to the I/O interfaces 544.The processor 540 may further utilize the real time clock 546 tosynchronize operation of the master controller 500 with other componentsof the bulk material handling system. In one embodiment, the real timeclock 546 comprises a M41T0M6 real time clock chip from STMicroelectronics.

FIG. 60 depicts additional details regarding an embodiment of auxiliarycontrollers 305. Each of the auxiliary controllers 305 in the depictedembodiment comprises a local power supply 550, one or more movementsensors 552, one or more temperature sensors 554, one or more signalinterfaces 556, and a processor 558. The local power supply 550 receivespower from the main supply block 520. The local power supply 550conditions and/or transforms the power supplied by the main supply block520 to provide components of the auxiliary controller 305 withappropriate power signals.

The movement sensors 552 are generally operable to detect movement ofthe auxiliary controller 305, the bulk material handling apparatus 4,the bulk material handling accessory 6, the bulk material, and/or acomponent of the apparatus 4 or the accessory 6. To this end, themovement sensor 552 may comprise sensors that detect changes indisplacement, changes in velocity, changes in acceleration, and/or otherindications of movement. In one embodiment, the movement sensor 552comprise a plurality of accelerometers where one accelerometer measuresacceleration of the arm 212 and another accelerometer measures gradientor tilt of the arm 212.

The accelerometers of one embodiment have a very small size, extendedtemperature range (operating range −55 . . . +125° C., with guaranteedspecifications at least in the −40 . . . +100° C. range), and thecapability of withstanding shocks of at least 2000 g. In particular, theaccelerometers may comprise MEMS (Micro Electro Mechanical System) typewhich typically are very small size and are capable of generatinggradient information with only a simple low pass filter. In oneembodiment, the accelerometers for measuring acceleration comprise theADXL78 accelerometer, and the accelerometers used for measuring the tiltcomprise the ADXL322 accelerometer both made by Analog Devices.Furthermore, in one embodiment, the accelerometers are placed on thesame printed circuit board as the processor 558 and near analog inputsof the processor 558. Furthermore, the accelerometers are placed awayfrom pulse width modulation outputs of the processor 558 to reduceelectric noise that may corrupt the accelerometers signal.

The temperature sensor 554 generates an analog measurement signal thatis representative of temperature sensed by the temperature sensor 554.In an embodiment, the temperature sensor 554 has a measurement range of−40° C. to +125° C. Furthermore, the temperature sensor in oneembodiment comprises an AD7416ARM temperature sensor from Analog Devicesalthough other sensors may be used.

The signal interfaces 556 may receive measurement signals from thesensors 552, 554 and condition such signals such that they are in a formsuitable for inputs of the processor 558. Assuming the sensors 552, 554generate analog measurement signals that are to be supplied to analoginputs of the processor 558, the signal interface 556 may filter,amplify, attenuate or otherwise adjust such measurement signals suchthat conditioned measurement signals remain within an operating range ofthe analog inputs of the processor 558. Similarly, if the analogmeasurement signals are to be supplied to digital inputs of theprocessor 558, the signal interfaces 556 may filter, amplify, attenuate,digitize or otherwise adjust the measurement signals such that thedigitized values of the measurement signals remain within an input rangeof the processor 558. Likewise, the signal interfaces 556 may conditioncontrol signals generated by the processor 558 such that such controlsignals remain within operating ranges of those components receiving thecontrol signals. Again, such conditioning may encompass filtering,amplifying, attenuating, and/or digitizing such control signals.

The processor 558 receives the conditioned measurement signals from thesensors 552, 554 and provides an output control signal to its respectivedamper 304 via a signal interface 556. In one embodiment, the processor558 comprises either TMS320LF2401 or TMS320F2801 digital signalprocessor from Texas Instruments although other digital signalprocessors, general purpose processors, and/or microcontrollers may beused. The processor 558 in one embodiment comprises a data acquisitionblock 560, a digital filter 562, integrators 564, 566, a peak converter568, an average converter 570, and root mean square (RMS) converter 572,a signal selector 576, a proportional-integral-derivative (PID)controller 578, and a pulse width modulation (PWM) controller 578. Oneskilled in the art should appreciate that many of the functionalcomponents of the processor 558 may be implemented as specializedhardware circuitry and/or software executed by general purposecircuitry.

The data acquisition block 560 receives conditioned measurement signalsfrom the sensors 552, 554 via the signal interfaces 556 and convertssuch analog signals into digital samples that are representative of thereceived signals. In one embodiment, the data acquisition block 552, 554receives measurement signals from two accelerometers 552 and thusgenerates two digitized signals therefrom. One digitized signal isrepresentative of acceleration of the arm 212 and the other digitizedsignal is representative of the tilt or gradient of the arm 212.

The digital filter 562 receives the digital signals from the dataacquisition block 560 and further filters the digital signal to removethe noise and limit the digital signal to an particular bandwidth. Inone embodiment, the digital filter 562 is implemented with a low groupdelay that is relatively constant within the operational bandwidth of 0to 250 Hz. In particular, one embodiment of the digital filter 562 isimplemented using a Remez exchange algorithm technique in order toreduce control error resulting from delay introduced by the digitalfilter 562 and other components of the auxiliary controller 305. In oneembodiment, the maximum delay in the processing chain including thefilter 562 is 13.7 us in order to maintain control error introduced bycontrol delay at an acceptable level.

The first integrator 564 in one embodiment receives a digital signalfrom the digital filter 562 that is representative of acceleration ofthe arm 212 and integrates the signal to obtain a digital signal that isrepresentative of velocity of the arm 212. Similarly, the secondintegrator 566 in one embodiment receives a digital signal from thefirst integrator 564 that is representative of velocity and integratesthe signal to obtain a digital signal that is representative ofdisplacement of the arm 212. The peak converter 568, average converter570, and the RMS converter 572 each receives the digital signals fromthe digital filter 562 and the integrators 564, 566 and generates outputsignals that respectively represent the peak values, average values andRMS values of the received signals during an analysis period. In oneembodiment, the analysis period is set to 0.5 seconds. However, the peakconverter 568, average converter 570 and RMS converter 572 in oneembodiment may be programmed with an analysis period between the rangeof 50 microseconds to over 3 seconds.

The signal selector 574 receives the digital signals from the digitalfilter 562, the integrators 564, 566, and the converters 568. 570, 572and selects signals of interest for the PID controller 576. In oneembodiment, the signal selector 574 represents a function implemented bysoftware that allows other software components of the auxiliarycontroller 305 to select signals for a control algorithm.

The PID controller 576 receives selected signals from the signalselector and generates a digital control signal based thereupon. In oneembodiment, the PID controller 576 processes the selected signals basedupon a control algorithm designed to control the bulk material handlingaccessory 6 in a desired manner. As will be explained below, the PIDcontroller 576 in one embodiment generates the control signal based upona damping control algorithm that attempts to maintain the scraper blades214 of arms 212 in contact with belt surface 84 with an appropriatecontact force which reduces chatter and scraper blade induced damage tothe belt 82.

The PWM controller 578 receives the digital control signal and convertsthe digital control signal to an analog control signal. In particular,the PWM controller 578 generates the analog control signal with a pulsehaving a width that is proportional to the value of the digital controlsignal.

Damping Control

As mentioned above, the auxiliary controllers 305 control the dampeningeffect of the controlled dampers 304. In particular, the auxiliarycontroller 305 in one embodiment generates a control signal for itsdamper 304 based upon measurement signals that are indicative ofacceleration of the arm 212. More specifically, the auxiliary controller305 generates the control signal based upon a control algorithm thatattempts to maintain proper cleaning pressure between the cleaningmechanism 86 and the conveyor belt 82, to reduce effects of shocksinduced by large belt defects, and to reduce wearing effects on the belt82, cleaning mechanism 86, and other mechanical components.

During operation of the belt cleaning mechanism 86, the belt cleaner arm212 does not precisely follow the shape of the conveyor belt 82 due theinability of the belt cleaning mechanism 86 to react instantly tochanges in the conveyor belt 82. Despite manufacturing intent, thesurface 84 of the conveyor belt 82 is not completely even. Theunevenness of the belt 82 results in the distance between the tips 260of the scraper blades 214 and the belt 82 changing since belt cleaningmechanism 86 is unable to react instantly to such changes in the belt82. The distance between the tips 260 and the belt surface 84 is furtherinfluenced by belt sag, major belt defects, and friction. Belt sags tendto induce relatively slow motion (e.g. several Hz) of belt surface 84and the tips 260. However, major belt defects commonly induce fastmotion (e.g. tens or hundreds of Hz) of the tips 260 as a result of thetips striking the major belt defects. Further, even without major beltdefects, friction between the tips 260 and the belt surface 84 resultsin the tips 260 being pushed away from the surface 84.

The controlled dampers 304 have a dampening effect which may berepresented by a damping coefficient c. In one embodiment, the dampingcoefficient c is linear with respect to the current of the controlsignal applied to the controlled dampers 304. Software of the auxiliarycontrollers 305 causes the processors 558 to select via the signalselector 574 from available status signals such as displacement signals,velocity signals, acceleration signals, peak signals, average signals,and RMS signals and determine the current of the control signal to applyto the dampers 304 in order to obtain a desired damping.

The status signal used by the auxiliary controllers 305 to control thedampers 304 may be one or more of the status signals applied to thesignal selector 574. In the one embodiment, the auxiliary controllers305 generate the control signals based upon the derived displacementsignals. However, those skilled in the art should appreciate that one ormore of the other status signals may be useful for other bulk materialhandling apparatus 6 or other embodiments of the belt cleaner apparatus80. Further, it should be appreciated that since displacement signal inthe present embodiment is calculated or derived from the accelerationsignal, the displacement signal may not correspond to the actualdisplacement but rather a value proportional to the actual displacement.

Through mathematical analysis and extensive experimentation it has beendetermined that appropriate results are achieved when the control signaland the status signal exhibit the relationship depicted in FIGS. 61-64.One skilled in the art will recognize that other shapes or profiles arepossible.

As shown in the examples in FIGS. 61-64, the damping, as reflected bythe control signal C, is dependent upon the status signal. The controlsignal C has a minimum value C₁ that corresponds to the minimum dampingfor a fail-safe feature. The control signal C also has a maximum valueC₂ that corresponds to the maximum damping for a safe and stable system.The minimum value C₁ and the maximum value C₂ may be determined fromdatasheets of the dampers 304 and analysis of the bulk material handlingsystem.

FIGS. 61-64 further depict system parameters S₁, S₂, S₃, and S₄. Thesystem parameters S₁, S₂, S₃, and S₄ correspond to values of the statussignal such as acceleration, velocity, or displacement. In oneembodiment, the auxiliary controller 305 controls the damping based upona displacement status signal and as such the system parameters S₁, S₂,S₃, and S₄ correspond to various displacement values. As depicted, thedisplacement is plotted against the x axis whereas the current of thecontrol signal is plotted against the y axis. As such, the 0 location onthe x axis in one embodiment corresponds to the belt cleaner mechanism86 being in an initial position with the scrapper blades 214 engagedwith the belt surface 84. Further, positive displacement valuescorrespond to the belt 82 pushing the scrapper blades 214 away thusresulting in mechanical energy being transferred from the belt 82 to thecleaner arm 212. Conversely, negative displacement values correspond tothe belt 82 returning to its initial position and the belt cleaner arm212 releasing the mechanical energy through the dampers 304, friction,etc. By changing the system parameters, S₁, S₂, S₃, and S₄, variouslevels of cleaning efficiency, blade wearing, and arm/frame vibrationsmay be achieved.

In a practical installation, a technician sets the system parameters S₁,S₂, S₃, and S₄ based on experience, system physical size, beltcharacteristics, and conveyed material characteristics. A technician mayanalyze the system behavior and change the coefficients S₁, S₂, S₃, andS₄ in such a way as to improve the parameters that are the mostimportant for that particular application at that time. For example,because of heavy rains, conveyed material may become wet and sticky.Therefore the technician may decide to temporarily increase the pressureexerted by the scraper blades 212 against the belt surface 84. Toachieve this goal, the technician may increase the minimum value C₁ thusincreasing the minimum value of the control signal.

Additionally, the control signal plots need not be symmetrical. In someinstances, asymmetrical control signal patterns may prove to be useful.The reason for this behavior is that if the right side has a moreshallow slope then the mechanical energy absorbed from the externalforce is lower since the coupling factor is lower. If the left side hasa steeper slope the mechanical energy dispersed to the environment ishigher since the coupling factor is higher. In one embodiment, themanufacturer and later on the technician may choose the controlparameters C₁, C₂, S₁, S₂, S₃, S₄ with the goal of reducing the spectralcomponents in the displacement error. By transferring a signal from thetime domain to the frequency domain (Fourier Transform) the energycontent is preserved. This is a direct consequence of the WienerKhintchine theorem (the power spectral density of awide-sense-stationary random process is the Fourier Transform of thecorresponding autocorrelation function). Therefore by analyzing thedisplacement error spectrum in the frequency domain, it is possible toselect parameters that reduce the error. To permit this selection ofparameters, the bulk material handling controller 12 may collect dataand may execute the configuration algorithm described below to determinethe control parameters for reduced displacement error.

Configuration of Damping Control

FIG. 65 depicts a method used by each of the auxiliary controllers 305to configure system parameters C₁, C₂, S₁, S₂, S₃, and S₄ that are usedto generate control signals. In block 602, the auxiliary controller 305selects a first set of values for the system parameters C₁, C₂, S₁, S₂,S₃, and S₄. For example, the auxiliary controller 305 may select thesystem parameters as follows: S₁=−2 mm, S₂=−1 mm, S₃=0 mm, S₄=5 mm,C₁=C_(min), C₂=C_(max). In block 604, the auxiliary controller 305configures the auxiliary controllers 305 with the selected parametersand collects data regarding the status signals from the auxiliarycontrollers 305 for a configuration cycle. In one embodiment, theauxiliary controller 305 records the displacement error x(t) over theconfiguration cycle. Further, the configuration cycle in one embodimentis defined as 1.5 seconds which is large enough to include at least onefull period of the excitation caused by sag of the belt 82. For oneembodiment of the conveyor belt cleaner 80, belt sag is the excitationwith the largest period. Other excitations such as friction or beltdefect typically have a shorter period. However, it should beappreciated that for other embodiments of the conveyor belt cleaner 80or for other bulk material accessories 6 a different configurationperiod may be selected which accounts for the largest excitation periodof interest.

The auxiliary controller 305 in block 606 calculates a cost value fromthe collected data which provides a measure of the effectiveness of thebulk material handling controller 12 when operating based upon theselected system parameters C₁, C₂, S₁, S₂, S₃, and S₄. In oneembodiment, the auxiliary controller 305 for each displacement errorx(t) computes its discrete Fast Fourier Transform (FFT) f_(x)[i] where iis the harmonic order. Then, the auxiliary controller 305 computes foreach f_(x)(i) set the cost function defined as the root means squarecontribution:

${R_{x} = \sqrt{\frac{\sum\limits_{i = 0}^{n}{f_{x}\lbrack i\rbrack}}{n}}},$

where n represents the number of relevant harmonics found in f_(x)[i].In one embodiment, the number of relevant harmonics is 55 times theexcitation frequency. However, for ease of calculation in a smallembedded system n=64 being the smallest power of 2 that is larger than55.

In one embodiment, the auxiliary controller 305 attempts to select thesystem parameters C₁, C₂, S₁, S₂, S₃, and S₄ such that overalldisplacement error is reduced in order to maintain the scraper blades214 appropriately biased against the surface 84 of the conveyor belt 82.However, it is possible to design other configuration methods thatattempt to reduce the response time or the overshoot, thus configuringthe auxiliary controllers 305 to account for other aspects that may bemore important to operation of certain types of bulk material handlingaccessories 6. For example, if the goal of the configuration method isto reduce the overshoot, the cost function may be replaced with a newcost function defined as:

R _(x)=max(|x[i]|)_(i=0 . . . n),

where max( ) is a function extracting the maximum from the list ofabsolute values of the displacement error x.

The auxiliary controller 305 then records in block 608 the calculatedcost value and associated set of selected parameters C₁, C₂, S₁, S₂, S₃,and S₄. The auxiliary controller 305 then in block 610 decides whetherto perform another configuration cycle. In one embodiment, the auxiliarycontroller 305 iterates through possible values for the systemparameters C₁, C₂, S₁, S₂, S₃, and S₄ and elects to repeat anotherconfiguration cycle if further possible values remain. In anotherembodiment, the auxiliary controller 305 iterates through possiblevalues until either a specified cost value is satisfied or until allvalues have been tested. For example, the auxiliary controller 305 maybe configured to stop once a set of parameters results in an error(cost) below a defined threshold amount.

In block 612, the auxiliary controller 305 selects a set of parametersC₁, C₂, S₁, S₂, S₃, and S₄ based upon their associated cost valuesR_(x)[i]. In one embodiment, the auxiliary controller 305 attempts tominimize the cost or displacement error x(t) and as such selects the setof parameters C₁, C₂, S₁, S₂, S₃, and S₄ associated with the smallestcost R_(x)[i]. However, it should be appreciated that for other costfunctions or other embodiments the auxiliary controller 305 may attemptto maximize the cost value for some aspect of the bulk material handlingaccessory 6. In such an embodiment, the auxiliary controller 305 thenmay select the set of parameters C₁, C₂, S₁, S₂, S₃, and S₄ associatedwith the largest cost value.

While the auxiliary controllers 305 may execute the method of FIG. 65 inorder to initially set system parameters C₁, C₂, S₁, S₂, S₃, and S₄, theauxiliary controller 305 may also execute the method in response toother events. For example, a technician may request the auxiliarycontrollers 305 to execute the configuration method when operatingconditions change. For example, a technician may request the auxiliarycontrollers 305 to execute the configuration method in response to a newconveyor belt, new conveyed material, change in speed, change inhumidity, etc. Moreover, the auxiliary controller 305 may periodicallyslightly change the control parameters C₁, C₂, S₁, S₂, S₃, and S₄ tocheck if a new control set of parameters provides better results.

By running the configuration method in a simulation environment such asthe SciLab, Octave, or Matlab, it has been determined that for themechanical parameters used in the simulations, the control parameters ofC₂=C_(max), C₁=C_(min), S₁=S₂=−1 mm, S₃=5 mm, S₄=10 mm provideappropriate results for one embodiment of the belt cleaner 80. As aresult, these values are used as a default control set in oneembodiment.

Safety Management

A safety management method which may be executed by the mastercontroller 500 is depicted in FIG. 66. While FIG. 66 depicts the methodas a sequential series of steps, those skilled in the art shouldappreciate that some embodiments may execute the steps in a differentorder and may execute certain steps in a parallel or pseudo-parallelfashion. In block 630, the master controller 500 receives movementsignals from the auxiliary controllers 305 that represent movementcharacteristics of the arm 212. For example, the master controller 500may receive from the auxiliary controllers 305 one or more of theacceleration, velocity, displacement, peak, average, and/or RMS statussignals.

The master controller 500 then in block 632 may determine whether themovement of the arm 212 is acceptable or whether some protective actionis to be taken in order to maintain safety. The following description isin regard to making a determination based upon received accelerationstatus signals. However, it should be appreciated that a similar schememay be used to make such a determination based upon velocity,displacement, peak, average and/or RMS status signals. In oneembodiment, the master controller 500 basically defines three protectionzones. An upper zone corresponds to acceleration values that are greaterthan a programmed upper threshold a_(max). A lower zone corresponds toacceleration values that are lower than a programmed lower thresholda_(min). A middle zone corresponds to acceleration values that fallbetween the upper threshold a_(max) and the lower threshold a_(min). Ifthe acceleration status signal indicates acceleration in the upper zone,then the master controller 500 determines to take protective action andproceeds to block 642 in order to take such action. Conversely, if theacceleration status signal indicates acceleration in the lower zone,then the master controller 500 determines not to take protective actionand proceeds to block 634 in order to determine whether to takeprotective action based upon a temperature status signal.

For accelerations that fall in the middle protection zone, the mastercontroller 500 triggers protective action in a delayed manner with adelay defined as:

t=k _(t) ·e ^(−α·k) ^(c) ,

where α represents the instantaneous acceleration, and k_(t) and k_(c)are predetermined coefficients. In one embodiment, the upper threshold,lower threshold, and coefficients are defined as: a_(max)=500 m/s²;a_(min)=250 m/s²; k_(t)=10000; and k_(c)= 1/32. By delaying response foraccelerations falling in the middle zone, the master controller 500permits the bulk material handling accessory 6 to have short timeperiods of accelerations in the middle zone, but triggers protectiveaction if accelerations above the lower threshold remain for an extendedperiod of time.

In addition to the above three protection zones, a technician may usethe user interface 8 to define limits regarding differences inacceleration, velocity, and displacement between adjacent arms 212 ofthe belt cleaner 80. If the master controller 500 determines thatmovement of adjacent arms 212 differs by an amount that exceeds thethresholds set by the technician, then the master controller 500 maydetermine to proceed to block 642 to take protective action. One reasonthe arms 212 may experience different movement is that the cleanermechanism 86 may not be properly mounted thus resulting in the arms 212not being properly aligned to the conveyor belt 82. Another reason isthat the belt 82 may have been damaged locally resulting in oneauxiliary controller 305 sustaining significantly higher shocks.Regardless of the cause, substantial differences in movement between thearms 212 is an indication of potentially unsafe operation of the beltcleaner 80, thus prompting the master controller 500 to take action.

If the movement is acceptable, then the master controller 500 in block634 may receive temperature status signals from the auxiliarycontrollers 305 and may determine in block 636 whether the temperaturereported by the received status signals is acceptable. In oneembodiment, if the temperature reported by an auxiliary controller 305leaves a specified range, the master controller 500 determines toproceed to block 642 to take protective action. A technician in oneembodiment may use the user interface 8 to set the temperature limitaccording to the conveyor belt material, conveyed material, regulations,and other environment conditions. For example in potentially explosiveenvironments, the temperature limit may be dictated by the flammabilityof that particular environment.

In block 638, the master controller 500 may receive status signals fromthe master supply block 520 and the local power supplies 550 regardingthe power supply capabilities of the respective units. The mastercontroller 500 in block 640 may determine based upon the received statussignals for the power supplies whether to take protective action. In oneembodiment, the master controller 500 proceeds to block 642 to takeprotective action if any local power supply 550 is not fully functionalor the master supply block 520 fluctuates outside of some safe limits.

In block 642, the master controller 500 takes protective action. In oneembodiment, the master controller 500 generates control signals whichcause the positioning mechanisms 530 to retract the cleaner mechanism 86with all arms 212 away from the belt 82. Further, the master controller500 may inform a technician via the user interface 8 regarding theprotective action taken and/or the cause of the protective action.

In addition to the above protective measures, the conveyor belt cleaner80 in one embodiment comprises further protective features. Inparticular, the dampers 304 of the belt cleaner arms 212 in oneembodiment are pre-biased at the minimum damping value C₁. As a result,if bulk material handling controller 12 fails, the damping automaticallyswitches to a low and safe value and stays that way until themaintenance technician restores the fully operational state. Further,pre-biasing protects the dampers 304 as such devices may be destroyed bylarge swings if the damper coil is left without power supply.

Activity Monitoring & Functional Data Storage (AM&FDS)

The main controller 500 in one embodiment interrogates each auxiliarycontroller 305 in order to obtain movement, temperature and other statusdata therefrom. In one embodiment, the main controller 500 periodicallyinterrogates the auxiliary controllers 305 for such data. In anotherembodiment, instead of interrogating each of the auxiliary controllers305, the auxiliary controllers 305 periodically send the mastercontroller 500 collected status information. Regardless of how themaster controller 500 obtains the data from the auxiliary controllers305, the master controller 500 in one embodiment maintains an activitylog that includes the operational values of each arm 212, time stampssuch values and corresponding parameters that have been used to operatethe arms 212. The corresponding parameters include the measured andderived values as described above and other values like the range ofsafe operation for each safety feature.

The main controller 500 may store all this information in memory 542 andmakes such data available to local or remote users via the userinterface 8. When the local memory 542 is full, the main controller 500may generally remove older data to make room for newer data. However,certain data which is deemed more important such as, for example, usercommands received via the user interface 8 may be kept for longerperiods for legal and safety reasons.

As previously described, each auxiliary controller 305 in one embodimenthas the capability of measuring or estimating through computations thefollowing real-time values: acceleration, velocity, displacement, arminclination (tilt), and temperature. Further, each auxiliary controller305 is capable to compute for each measured sample of acceleration,velocity, and displacement the following values: average, peak, rootmean square value. These values can be used by the master controller 500to monitor system activity and make adjustments to the components.

The master controller 500 for example may determine the working statusof each arm 212 based upon the arm inclination. In particular, themaster controller 500 may interrogate each auxiliary controller 305 on aregular basis. Therefore, the master controller 500 may maintain a logof arm inclination data for each arm 212. The master controller 500 maymaintain the logs such that the first arm inclination entry for each arm212 corresponds to an arm inclination reference at the time ofinstallation. The master controller 500 may then use the arm inclinationdata to measure wear of the belt 82 since as the belt 82 wears the angleor inclination of the arms 212 changes.

The master controller 500 may further monitor belt loading and/or thecomposition of the conveyed material based upon status signals receivedfrom the auxiliary controllers 305. In particular, the master controller500 may monitor the displacement of each arm 212 and determine theloading of the belt 82 based upon variation of the displacement. Asshown in FIG. 67, displacement of the arms 212 is indicative of theloading on the belt 82. As it could be seen from FIG. 67, the initialdisplacement is near zero indicating an empty conveyor belt. Later on,the displacement shows increased values indicating various degrees ofloading. Moreover, the master controller 500 may utilize this techniqueof monitoring the displacement of the arms 212 as an indication of thebelt clogging.

Various features of the invention have been particularly shown anddescribed in connection with the illustrated embodiment of theinvention, however, it must be understood that these particulararrangements merely illustrate, and that the invention is to be givenits fullest interpretation.

1.-30. (canceled)
 31. A method of dampening vibration of a scraper blade of a bulk material handling accessory with respect to a conveyor belt, said method comprising the steps of: providing a damper having a piston and a housing including a fluid chamber, said piston including a piston head located within said fluid chamber and a shaft extending outwardly from said housing and adapted to be coupled to the scraper blade, said piston head separating said fluid chamber into first and second sub-chambers located on respective sides of said piston head, said piston head forming one or more fluid passages extending between said first and second sub-chambers such that fluid within said fluid chamber may flow between said first and second sub-chambers through said fluid passages in response to movement of said piston head within said fluid chamber and with respect to said housing, said fluid having a viscosity; changing said viscosity of said fluid in said fluid chamber to modify the damping characteristics of said damper in response to changes in the operating conditions of the scraper blade.
 32. The method of claim 31 wherein said piston head includes an electric coil adapted to generate a magnetic field, said method including the step of changing the magnetic field generated by said electric coil to change the viscosity of the fluid.
 33. The method of claim 31 including the step of providing a magnetic field to the fluid in the fluid chamber, and selectively changing the magnetic field to change the viscosity of the fluid.
 34. The method of claim 31 including the step of providing an electric field to the fluid in the fluid chamber, and selectively changing the electric field to change the viscosity of the fluid.
 35. The method of claim 31 including the step of transferring kinetic energy generated by vibration of the scraper blade to said piston of said damper, transferring kinetic energy from said piston to said fluid in said fluid chamber and converting the kinetic energy transferred to said fluid into heat, and transferring the heat to the atmosphere. 